Antiskid unit and method of making the same



Sept. 27, 1938. H. H. RINEHART 2,131,571.

ANTISKID UNIT AND METHODOF MAKING; THE SAME Filed Aug. 18, 1934 INVENTOR. HarryH.Rims-hart.

BY Ska @4541 ATTORNEY.

' Patented Sept. 27, 1938 UNITED STATES PATENT OFFICE ANTIS-KID Um AND METHOD or MAKING THE SAME Harry H. Rineliart, New Market, N. 1., assignor to Johns-Manville Corporation, New York, N. Y., a corporation of New York Application-August 18, 1934, Serial No..'i40,429

2 Claims.

This invention relates to an antiskid unit and to the method of manufacturing the same.

There are in wide use, at this time, slabs of so-called asphalt plank comprising asphalt, re-

enforcing fibres of rag stockor asbestos, inorganic 4 filler material such as cinders, and, suitably, also a limited proportion of finely divided filler of theconventional flbre-reenforced asphaltplank, of

the type described, and having an adequate coeiflcient of friction to insure antiskid functions. Another object is to provide such a unit having antiskid material locked into the base material and exposed on the face of the unit. Another in which'the antiskid material is in continuous strips but is somewhat yieldable and, therefore, not susceptible to being cracked or broken when heavy traflic passes thereover. Other objects and advantages will appear from the detailed descripe tion that follows.

The units of the present type are adapted for use as traffic-bearing surfacing material, as in highway pavements, sidewalks, and flooring of factories.

Embodiments of the invention that are preferred at the present time will bedescribed in connection withthe drawing in which Fig. 1 is an end view of a fibre-reenforced asphalt plank provided with closely spaced grooves and suitable for use as the base material;

Fig. 2 is a perspective view of a portion of a strip of material of high coefficient of friction adapted to be engaged in one of the said'grooves;

Fig. 3 is a perspective view of a finished antiskid unit in which antiskid materialofthe type illustrated in Fig. 2 is disposed and locked within initially of the type il- 1; and

Fig. 6 is an end view of a modification of the I invention in which antiskid material is disposed over the complete face of the unit and is locked so in position in grooves in the base material.

object of the invention is to provide such a unit-- base material initially of type illustrated in Fig.

There are shown units comprising base material I of the type of the flbre-reenforced asphalt slab or plank described. o

Such base material may be made by a conventional process and from conventional ingredients in usual proportions. Thus, there may be formed an intimate, plastic, .hot mixture of asphalt,

- shredded cotton rags, and cinders. The composition is made into a mixture, at an elevated temperature adapted to render the asphalt fluent,

and is then extruded through a" suitable orifice or between properly spaced rolls to form a slab that may be, for example, 2 inches thick and 8 inches wide and may be'cut to a length of 8 feet. 1f

The extrusion nozzleior equipment may be provided with meansi'or forming ina face of the. slab spaced grooves 2 that, as formed, may have vertical sides or may be wider at the bottom than at the top, as illustrated, for example, in Fig. 6.

Alternatively,-'the slab formed initially into a vided subsequently with grooves of theshape desired, as by means of saws or other cutting means.

After.the grooved slab has been made, and, suitably, while it is still warm and the asphalt therein is in readily fiowablecondition, there is 2'0 rectangular unit of-plane surface'may be pro.-

inserted in each of the grooves a strip 3 ofantiskid material. This antiskid material should have a relatively'high coetllcient of friction and should be semi'rigid or somewhat yieldable, to avoid breaking under load applied to the face of the unit containingthe said material. There may be used, for example, preformed strips of a highly compressed and then hardened composition of Portland cement, asbestos fibres, cinders,

and water, this material being representative 'of The strips 3 may be chamfered, that, ,1...-

rower on the face I than on the back 5, in-order to promote the subsequent locking of the strips in the grooves, as will be described.

After the strips 3 have been inserted into 110- I sition in the corresponding grooves 2, the result-- In this ing composite product is die-pressed. operation pressure is exerted from all sides, preferably while the asphalt in the unit is in warm condition. The pressing maybe done 'in a die having plates contacting with face and back andx the four edges oithe composite, whereby flowing th the strips 3 is obtained.- e product is en hardened. as by being allowed to cool to atniospheric temperature. Strips G of antiskid material having, for example, brokemedges of irregular contour, providing irregularities including recesses 31,- may 'fithe asphalt into tight, conform engagement be used in place of the strips 3 and inserted into grooves I. The resulting compositesmaywo then be compressed as described above, to force the base material of the edges of the grooves into the recesses and thus lock the strips in position, as shown in Fig. 5.

The strips 3 and 6 are alike in having inferior portions of the side edges extending beyond su- ,perior portions, in certain localized areas at least. The antiskid material is locked in position by engagement of the base material above such projecting inferior portions, as, for example, in the recesses I or against chamfered edges of the strip 3.

Preferably, the antiskid material fills the arators II, as illustrated in Fig. 3. These dividers may be composed of conventional joint filler land cement, sand and fine gravel and then almaterial, wood, or the like.

If desired, the strips may be composed of other materials of high coefiicient of friction than that previously described. Thus, the said strips may consist of granules of coarse sand, fine gravel or a sand-gravel mixture and a binder of the type of an asphalt adhering the granules into a unit, the proportion ofbinder being suitably of the order of 10 parts by weight to 100 parts of total weight of the antiskid material.

Such a composition is shown, for instance, in

Fig. 6. In the modification of the invention thereshown, granules 8 such as fine gravel or the like are bonded by a binder 9 of the type of an asphalt into an antiskid material disposed within the grooves, as illustrated. Antiskid material of this nature may be applied to the grooves at an elevated temperature, adapted to render fluent the binder therein, and may be hardened in situ, as by cooling.

If desired, additional antiskid material may be disposed over the face of the unit and over the antiskid material filling the grooves, to give a continuous surface of antiskid material, as illustrated in 'Fig. 6. In such a case, the said additional antiskid material is'firmly adhered to the base material at positions Ill and, also, to the antiskid material previously applied in the grooves. Thus, when the binder in the antifriction material is thermoplastic, the additional antiskid material may be'applied over the surface at an elevated temperature adapted to renderfiuent the thermoplastic binder and cause adherence to the base material to which it is applied, suitably under the influence of pressure as by means of a pressure roll. The grooves in the basematerial shown in Fig. 6 provide means for looking the antiskid material in position as by being .wider at the base than at'the top of the groove. In such a structure, the antiskid material is so locked in position as not to be disengaged during even severe use, as, for example, by the tires of anautomobile passing thereover and being subjected to strong braking action.

While various dimensions of units and strips may be made, I have found particularly satisfactory strips of antiskid material that are approximately one-fourth as thick as the overall thickness of the base material into which they are locked. Also, I have found satisfactory the use of the antiskid material in strips that are of the order of 0.5 to 1.5 inches wide at the exposed face and are closely spaced, say spaced apart at their edges by approximately the width of the individual strips, to expose about equal areas of material having low and high coeflicients of friction, respectively.

While the invention has been illustrated by exampleswhich include the insertion of preformed antiskid units into recesses, such as grooves, in the base material, it will be understood that, as

heretofore pointed out, antiskid material in other conditions may be inserted in the recesses. Thus, antiskid material in plastic (flowable) condition may be used to fill the recesses such as,

the series of longitudinally extending grooves 2 and allowed toharden in situ. For example, I may form an asphalt plank of the type described,

provided with recesses in the face portion thereof that is to be exposed during use, pour into the recesses a flowable antiskid composition adapted to be hardened into a rigid material, say, of the type of a concrete containing Portlow the antiskid composition to harden. If desired, the antiskid material may be applied while the base material or plank is warm and the asphalt therein is relatively soft and plastic. such a case, the hardening of base material or plank and the antiskid material associated therewith may be' undertaken simultaneously.

Before casting the cementitious antiskid material in the recesses, separators or dividers I of the type described may be first placed across the grooves at close intervals, as, for instance, 12

inches apart, andthe several spaces of relatively short length thus formed between these members ll filled with the cementitious composition. The members II at their upper surfaces should be approximately flush with the tops of the ridges between the recesses.

The term grooves is used herein to include any form' of recess or indentation in the face portion of the slab adapted to receive and hold antiskid material.

1 The details that have been given are for the purpose of illustration, not restriction, and variatio'ns therefrom may be made within the scope of the appended claims.

What I claim is: 1. A unit, adapted for use as traffic-bearing reenforced asphalt slab provided with closely spaced grooves in the face thereof that is to be exposed during use and antiskid material secured within the said grooves, the antiskid material comprising a semi-rigid fibre-reenforced cementitious composition in hardened condition,

surfacing material, comprising a preformed fibrepressing the resulting composite product from all directionswhile the slab is maintained in warm condition, whereby the asphaltis caused to conform to the sides of the said strips and the strips are, locked in position.

. HARRY H. RINEHART. 

